CN106471340A - For the device from multiple fiber sensor measuring optical signals - Google Patents

For the device from multiple fiber sensor measuring optical signals Download PDF

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Publication number
CN106471340A
CN106471340A CN201580030292.6A CN201580030292A CN106471340A CN 106471340 A CN106471340 A CN 106471340A CN 201580030292 A CN201580030292 A CN 201580030292A CN 106471340 A CN106471340 A CN 106471340A
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fbg
array
pulse
wavelength
light source
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CN106471340B (en
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F·欧莱特
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F. Ollett
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Kromah Sensi Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
    • G01D5/35354—Sensor working in reflection
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35383—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using multiple sensor devices using multiplexing techniques
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/0205—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
    • G01J3/0218—Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using optical fibers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28—Investigating the spectrum
    • G01J3/45—Interferometric spectrometry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/12—Generating the spectrum; Monochromators
    • G01J3/18—Generating the spectrum; Monochromators using diffraction elements, e.g. grating
    • G01J3/1895—Generating the spectrum; Monochromators using diffraction elements, e.g. grating using fiber Bragg gratings or gratings integrated in a waveguide

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Optical Transform (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Measuring Temperature Or Quantity Of Heat (AREA)

Abstract

This invention describes a sensor device.This device includes interrogator, and interrogator includes launching the light source with certain wavelength, and certain wavelength is about a mean wavelength；Configure with a Fiber Bragg Grating FBG (FBG).This configuration includes FBG array, and this array includes multiple multiple FBG in an optical fiber and is used for reflected impulse, produces reflected impulse therefore on each FBG.FBG on one given FBG array therebetween has a space interval, and this interval allows to be formed between the reflected impulse that each sensor produces on a sensor time difference.Described FBG array has a reflectance spectrum window, and this reflectance spectrum window includes mean wavelength.

Description

For the device from multiple fiber sensor measuring optical signals
To Cross-Reference to Related Applications
This application claims the priority of the U.S. Provisional Application in April 2 Application No. in 2014 " 61/973,975 "
Background
(a) technical field
Disclosed theme is usually directed to fibre opticss, more properly, the present invention relates to fiber Bragg grating sensor.
(b) background technology
Fiber Bragg Grating FBG (FBGs) has been found to be the efficient apparatus for monitoring physical parameter, physical parameter includes But it is not limited to, temperature, strain, pressure, vibration.FBG passes through the core of one optical fiber in given length (typically several millimeters) Permanent cycle variations in refractive index and manufacture.This equipment reflects to be propagated by the light of narrow wave-length coverage in a fiber.Instead Penetrating spectrum generally has a narrow peak value in wavelengths centered, and the screen periods that narrow peak value is equal in space are multiplied by the two of fiber refractive index Times.The width of reflectance spectrum and grating length are inversely proportional to.In order to FBG is used as sensor, conversion configurations are to the light comprising grating Fine change temperature or stretching section, both effects lead to the change of grating effective period, thus leading to reflect center wavelength of light Change.Therefore, the measurement of this centre wavelength can be associated with measured parameter (measured variable).Can be by emitting light into In the optical fiber of distant place, detect and analyze the spectral characteristic of reflected light and remotely measure.Because fibre loss is very low, measurement sets The standby position being placed on away from FBG.
FBG is optical fiber immunity electromagnetic interference so that they are possible to be applied to electricity as an advantage of sensing device In the environment of sensor or electronic sensor can not well execute.
But one of major advantage of FBG is, due to their narrow spectral characteristic, multiple FBG of different cycles are permissible It is written into the diverse location of a single optical fiber, and each FBG can be identified by spectral characteristic.And with individually A piece optical fiber, multiple locus can be sensed by measuring the peak wavelength of FBG simultaneously.Along an optical fiber, by multiple FBG The technology that sensor is combined from different centre wavelengths is referred to as wavelength-division multiplex (Wavelength Division ), or WDM Multiplexing.
The method being commonly used for monitoring the centre wavelength of FBG is tunable with multiple scanning width wave-length coverage Light source.Reflected light is collected by the optical circulator being arranged between light source and FBG or photo-coupler, is subsequently sent to photodetection On device.Peak value therefore in reflected light corresponds to each FBG peak reflectance wavelength.Or it is also possible to broadband light source, will own The centre wavelength of FBG falls into source spectrum.Then reflected light is sent to spectrogrph, is determined by analyzing spectrogrph data Reflection peak.
For WDM inquiry, all FBG along optical fiber have the light in tunable optical source or broadband light source There is centre wavelength in spectral limit.On the other hand, the wavelength spacing of each FBG must sufficiently large be affected with being contained in measured parameter The maximum spectral shift of each FBG lower, not have the probability of overlap between each spectrum, overlap will lead to fuzzy or mistake Measurement.One " spectrum window " (spectral window) therefore can be defined, that is, give under measured variable scope, FBG senses The centre wavelength scope that device may span across.As a result, the maximum quantity of the FBG that can be inquired by given light source, about etc. In spectral width or light source span divided by the spectrum window of separated sensor spectral width.
For example, the centre wavelength of typical FBG is in proportional shifting for strain, therefore, if strain that will be measured Up to 10,000 μ ε, then 10nm is approximated for a FBG maximum wavelength skew with 1550nm centre wavelength.If can Tuning source has the scope of 60nm, as typical commercial source, then the maximum quantity that can use the sensor in this source is 6, by Given 60nm is given divided by the 10nm of spectrum window.
Some applications will benefit because carrying greater number of sensor on same fiber.For example, for equipment part, For example, the temperature of the spatial analysis of the equipment part of wind turbine blade machine or generator amature or strain, it will benefit from There is the number of sensors of 100 or bigger scope.
A method increasing number of sensors is come distinguishing sensor with time domain and wavelength category.This scheme is labeled For time division multiplexing (Time-division-multiplexing), or TDM, in TDM scheme, for inquiring the light of grating Source is pulse modulated, and the pulse duration is set as being shorter than the optical path delay from a grating to next grating.If The maximum reflectivity of each grating is sufficiently small (typically 1%-2%), then the first reflection being only from each grating is aobvious Write, and the signal that on grating reflector, the light of multiple reflections reflects is negligible.Therefore each pulses generation is a series of Echo, echo can be distinguished in time.As WDM inquiry scheme, source can be tunable or wide band.Different Part is, detection means must have response time, and response time will the short enough reflection being come from numerous gratings with differentiation.Cause This, multiple FBG can be used in single spectrum window.Therefore, the sum that the sum of sensor configures for WDM is multiplied by can quilt The quantity of the sensor of timing separation.
Although this combination TDM-WDM inquiry scheme can use tunable source, the prior art that major part refers to Using broadband light source.Because broadband light source has there are all wavelengths for inquiring sensor in all times, this meaning Taste response time and is not limited by source.Tunable source always needs the whole span lengths of some time sweeps, and this time is Limit system response time eventually.
When using wide frequency light source, the centre wavelength of grating sensor is many times passed through with spectrum sensitivity filter (example As non-equilibrium interferometer) or radiological unit process reflected light determination.
Describe the prior art of TDM and WDM sensing device, including patent publication No. WO2013001268, CA2379900A1, US20100128258, WO2004056017, these patents all using broadband light source and various are configured to Gate (gate) reflected signal simultaneously detects their wavelength.
Niu Weizhasi (Niewczas) (WO2013001268A2) describes one kind broadband light source and interferometer measurement The system of reflected light wavelength.Cooper and Smith (CA2379900A1) also using pulse modulated broadband light source and Photomodulator gates (gate) reflected impulse.Wo Lantan and Li Aode (Volanthen and Lloyd) (US20100128258) Also using pulse broadband source.
Ai Waao and Li Aode (Everall and Lloyd) (WO2004056017) describes one kind with by semiconductor light Learn amplifier impulse modulation and the TDM system of gate broadband light source.With light filter known to propagation performance, or alternatively select Spectroanalysis instrument, band meter just can determine that wavelength.The application of semiconductor optical amplifier result in bigger optical power simultaneously (optical power), the synthesis cost of source, image intensifer and wavelength measuring equipment is still important.
When using broadband light source, a difficult point is that optical power can be assigned to whole light source spectrally.Cause This, the actual power being reflected by each FBG is only the sub-fraction of total source power.It is true that the major part of source power It is wasted, because it is not reflected by any sensor.Typical broadband light source, for example, light emitting diode or super spoke Penetrate light emitting diode after being coupled into single-mode fiber, only the power of 1mW.The low-power of reflected signal is difficult to obtain one enough Big signal to noise ratio.It is that the quantity composing window nevertheless suffers from the restriction of the total spectrum width in source using another difficult point of broadband light source.
Sum it up, most prior art is limited by extra defect, system cost.Image intensifer, fibre optic interferometer Or spectroanalysis instrument is all comparatively expensive device.At present, the high cost of these systems hinders their extensive application.Impact sets Another factor of standby expense is, this is an all-or-nothing apparatus.The meaning is, this apparatus energy under given cost Enough measure substantial amounts of grating, but if the capacity that the quantity of required sensor is less than final apparatus cannot reduce payment.
It is therefore desirable to improvement fibre-optical sensing device.
Content of the invention
According to an aspect of the invention, it is provided a kind of sensor device, including：Interrogator, including light source, each light Source transmitting has the pulse of certain wavelength, and described wavelength is around the corresponding mean wavelength of light source each described；With FBG battle array Row, one of corresponding described light source of each FBG array, and include multiple on an optical fiber for reflected impulse FBG, the FBG in wherein given FBG array therebetween has a space interval, and this interval be enough to Allow on receptor to be produced the time difference between reflected impulse by each sensor on given FBG array；Wherein Each described FBG has corresponding spectral reflectance window, and spectral reflectance window includes putting down accordingly of a corresponding described light source All wavelength；There is spectrum interval it is sufficient to allow on the receiver from described in each between the corresponding mean wavelength of wherein said light source SPECTRAL DIVERSITY between the pulse of FBG array reflection.
According to an embodiment, each described light source is configured to around the corresponding mean wavelength of each in described light source First respective wavelength and the transmitting pulse of the second respective wavelength.
According to an embodiment, described receptor includes processor, and described processor is applied to each described light source corresponding Each described FBG array, and the prior art of the reference reflectance spectrum based on each FBG, with being derived from The reflected wave pulses of the first corresponding pulses and the second corresponding pulses clearly determine the actual reflectance spectrum of each FBG Peakdeviation.
According to an embodiment, described FBG array is arranged on multiple optical fiber, each optical fiber have one to The FBG array of fixed number amount.
According to an embodiment, also include the multiplexer for being connected thereto multiple optical fiber, described interrogator It is optically coupled to multiplexer to be used for described pulsing to multiple optical fiber.
A kind of another fermentation according to the present invention, there is provided sensor device, including：Interrogator, has certain including transmitting The light source of the pulse of individual wavelength, described wavelength is around a mean wavelength；Configure with Fiber Bragg Grating FBG (FBG), including FBG Sensor array, described sensor array includes the multiple FBG on an optical fiber, and is used for reflected impulse, thus Reflected impulse is produced on each FBG, the FBG on one of given FBG array betwixt has One space interval, this space interval be enough to allow to be produced between reflected impulse by FBG each described on the receiver Time difference；Wherein FBG array has the spectral reflectance window including described mean wavelength.
According to an embodiment, described light source is used for being transmitted in the arteries and veins of first wave length and second wave length near mean wavelength Punching.
According to an embodiment, described receptor includes a processor, and described processor is based on described multiple FBG sensings The prior art of the reference reflectance spectrum of device, adaptation is with the reflection arteries and veins from the first corresponding wavelength and the second corresponding wavelength Punching clearly determines the actual reflectance spectrum of each of multiple FBG.
According to a further aspect in the invention, there is provided one kind is joined with Fiber Bragg Grating FBG (FBG) sensor for measurement Put the device of the optical signalling of interaction, described device includes：FBG array, sensor array sets along single optical fiber Put, each FBG is used for operating in given spectrum window, and FBG is separated along single optical fiber with given distance, in array On each FBG have a known reflectance spectrum, this reflectance spectrum can be displaced under prescribed conditions reality anti- Penetrate spectrally, thus defining a side-play amount；And interrogator, described interrogator is connected on single optical fiber and comprises mould Block, the described module discrete wavelength inquiry FBG array more than being included in given spectrum window, interrogator receives The reflection of the optical signal of the discrete wavelength more than of FBG, inclined with each FBG on array for the determination Shifting amount.
According to an embodiment, described module is with being included in two discrete wavelength interrogation FBG in given spectrum window Array.
According to an embodiment, the described given distance that FBG is spaced, lead to the optics being received by described interrogator Time difference between the reflection of signal.
According to an embodiment, also include a processor, described processor is operably connected to interrogator, and is adapted to Execute instruction is used for determining the instruction of specified criteria, under to described fixed condition it is known that reflectance spectrum be displaced on array In the actual reflectance spectrum of each FBG.
Another invention according to the present invention, there is provided one kind is joined with Fiber Bragg Grating FBG (FBG) sensor for measurement Put the device of the optical signalling of interaction, described device includes：Multiple FBG tactility apparatus arrays, sensor array is along in key light Multiple optical fiber settings that fibre branches out, each of the plurality of array has different spectrum windows and includes in difference spectrum window The FBG of operation, described FBG has a known reflectance spectrum, and this spectrum can experience in specified criteria partially Move, therefore side-play amount is defined to each FBG；Interrogator, is connected on main fiber and includes multiple modules, each module With a FBG corresponding more than the pulse interrogation of in the different spectrum windows of an array of corresponding FBG Array, interrogator receives the optical signalling of the side-play amount being reflected and indicated by FBG each FBG.
According to an embodiment, each module is using the different spectrum windows in the array of corresponding FBG more than one Pulse, the corresponding array inquiring corresponding FBG of inquiry, anti-clearly to evaluate known to each FBG Penetrate the side-play amount of spectrum.
According to an embodiment, the FBG of described given array is separated along one of multiple optical fiber with given distance, On optical fiber, FBG is configured to：When optical signalling is reflected by FBG, described optical signalling pulse can be produced Time difference.
According to an embodiment, also include a multiplexer, be arranged between interrogator and multiple array, multiplexing Device is used for for the output of multiple modules integrating with main fiber.
According to a further aspect in the invention, one kind is provided to be used for measuring Fiber Bragg Grating FBG (FBG) sensor configuration The device of optical signalling, described device includes：Along the array of the FBG of single optical fiber setting, each described FBG There is the known reflectance spectrum being centered around the peak reflectance wavelength of movement under change condition：And interrogator, described interrogator connection In independent optical fiber and include：Module, be adapted to using optical signalling inquire FBG array, described optical signalling with First wave length (λ+) or second wave length (λ-) transmitting pulse；And receptor, adaptation is to detect the arteries and veins being reflected by FBG array Punching, i.e. reflected impulse, for determining the side-play amount of the peak reflectance wavelength at least one FBG.
According to an embodiment, also include being arranged at the array of the additional FBG of additional optical fiber, each adds The array of FBG has different and unique peak reflectance wavelength；Described interrogator also includes additional module, adaptation Become the array of the FBG additional with different optical signalling inquiries, described optical signalling is included with first wave length (λ+) or the Two wavelength (λ-) pulse launched, wherein λ+And λ-It is different and unique for each additional module.
According to an embodiment, described receptor includes a photodiode, for optical signalling is changed into representative The electronic signal of described optical signalling.
According to an embodiment, described receptor includes an amplifier and is used for amplifying described electronic signal.
According to an embodiment, described receptor is used for the processing meanss with the electronic signal processing described receptor output Operation communication.
According to an embodiment, based on the side-play amount of peak reflectance wavelength, processor is adapted to defeated by locating reason receptor The electronic signal going out to determine act on measured at least one FBG.
According to an embodiment, described processing equipment is adapted to acting on the temperature at least one sensor for determining At least one of degree and strain.
According to an embodiment, also include swivel joint, described swivel joint is arranged at interrogator and described single Between optical fiber, it is used for making single optical fiber rotate with respect to described interrogator.
According to an embodiment, described interrogator includes light source, and light source includes laser diode.
According to an embodiment it is characterised in that also including cooling element, for keeping the temperature of described light source.
According to an embodiment, described cooling unit includes the cooling unit of thermoelectricity.
According to an embodiment, also include temperature sensor, for measuring the temperature of light source, and and then notify described cold But whether element is necessary to cool down described light source.
According to an embodiment, also include the reference laser diode for monitoring described optical signal.
According to an embodiment, described reference laser diode is the long-term wave length shift in order to monitor described light source.
According to an embodiment, also include photo-coupler, for the pulse steering of launching slave module to FBG device And reflected impulse is configured (or FBG device) (FBG sensor arrangement) from described FBG draw Lead described receptor, described photo-coupler has the second branch, wherein said reference photodiode is arranged on institute State in the second branch of photo-coupler.
According to an embodiment, also include photo-coupler, for pulse steering that will launch from described module to described FBG Sensor configuration, and described reflected impulse is directed to described receptor from the configuration of described FBG.
According to a further aspect in the invention, provide a kind of for measurement by include FBG Fiber Bragg Grating FBG (FBG) method of the optical signalling of sensing device reflection, the method comprising the steps of：Pass to described FBG from a light source Sensor configuration sends：At least one pulse in first wave length；With at least one pulse in second wave length, each pulse is at least Separated with time interval T, each pulse is shorter than unit interval T, for distinguishing the reflected impulse from each FBG； For at least one FBG, receive and measure following intensity：Reflection arteries and veins at least one pulse of first wave length Punching；With the reflected impulse of at least one pulse in second wave length, calculate the peak reflection ripple of at least one described FBG Long.
According to an embodiment, executed by receptor and receive and measurement intensity.
According to an embodiment, described receptor is adapted to sufficiently fast response and is derived from each sensor so that distinguishing Reflected impulse.
According to an embodiment, described time interval T be from adjacent FBG reflected impulse in described receptor On the time interval that received.
According to an embodiment, also include determining the reference value with respect to described peak reflectance wavelength for the described peak reflectance wavelength Side-play amount.
According to an embodiment, also include going determination to act at least one FBG with the side-play amount of described peak reflectance wavelength The value of the measured variable of sensor.
According to an embodiment, also include the wavelength with light source described in reference laser diode monitor.
According to an embodiment, also include the temperature using independent temperature sensor measurement reference laser diode.
According to an embodiment, also include controlling the temperature of described light source.
According to an embodiment, the temperature of light source is controlled to include：With the described light source of the cooling element cooling of thermoelectricity.
According to an embodiment, the temperature controlling light source is based on the input from temperature sensor, and described temperature sensor is surveyed Whether the temperature of amount light source deviates particular value.
According to an embodiment, it is sent at least one pulse of first wave length with the first intensity, is sent in the second intensity At least one pulse of second wave length, the intensity of wherein measurement reflected impulse includes detecting the disappearance of each pulse respective strengths.
According to an embodiment, configure transmission pulse to described FBG and include passing to the FBG being arranged on multiple optical fiber Sensor sends.
According to a further aspect in the invention, provide a kind of Fiber Bragg Grating FBG comprising FBG for inquiry (FBG) method of sensing configuration, the method comprising the steps of：Send multiple light letters to the FBG array of FBG configuration Number, each described optical signal is used for interacting with the described FBG on single FBG array, and each optical signal includes：Accordingly First wave length at least one pulse；With at least one pulse of corresponding second wave length, each described optical signals phase The mean wavelength answered is to characterize, and in each optical signal described, corresponding first and second wavelength provide around described mean wavelength： For at least one FBG of FBG array, receive and measure following intensity：At least one arteries and veins in described first wave length The reflected impulse of punching；Reflected impulse with least one pulse in described second pulse；And FBG at least one described is passed Sensor, calculates peak reflectance wavelength.
According to an embodiment, to each optical signal, each pulse is at least spaced corresponding time interval T, wherein each arteries and veins Punching is shorter than corresponding time interval T.
According to an embodiment, executed by receptor and receive and measurement intensity, described receptor response sufficiently fast with can Distinguish the reflected impulse from each FBG.
According to an embodiment, each FBG array has following characteristics：All FBG sensings of setting on each FBG array Corresponding spectrum window shared by device, and each FBG array is inquired with a corresponding optical signalling.
According to an embodiment, between the corresponding mean wavelength of each described optical signalling, exist more than each FBG battle array The corresponding spectrum composing window of row separates, enabling carry out spectrum difference to each FBG array.
Brief description
Combining accompanying drawing according to following detailed descriptions can be it will be apparent that shows the further feature and advantage of disclosure, its In：
Figure 1A illustrates that an embodiment includes inquiring the single mould of the serial array of the FBG along single optical fiber setting The installation drawing of block；
Figure 1A illustrates that an embodiment includes inquiring the single mould of the parallel array of the FBG along multiple fiber distribution The installation drawing of block；
Fig. 2A illustrates that an embodiment includes inquiring the many of multiple serial array of the FBG along multiple fiber distribution The installation drawing of individual module；
Fig. 2 B illustrates to comprise in an embodiment to inquire the many of multiple parallel arrays of the FBG along multiple fiber distribution The installation drawing of individual module；
Fig. 3 A to Fig. 3 C illustrates to launch the intensity with respect to the time with reflected impulse in an embodiment；
Fig. 4 A-4C illustrates the transmitting with respect to the time in another embodiment and the intensity of reflected impulse；
Fig. 5 A and Fig. 5 B illustrates the exemplary plot of a FBG reflectance spectrum；With
Fig. 6 A-6C is the installation drawing of the photodiode of the pulse illustrating that an embodiment is included for detection transmitting；
Fig. 7 a-7C is the figure of the various embodiments of output FBG array configuration；With
Fig. 8 is to illustrate to add in an embodiment/remove how multiplexer is transmitted into detached point from one or more modules Among figure；
It should be noted that in all of the figs, identical feature is indicated by the same numbers.
Specific embodiment
Disclosure is related to the device with reference to the multiple FBG of WDM and TDM commercial measurement.
Existing description describes the embodiment based on modular system, wherein each module low cost, building block system Become.And, user can build an instrument by the cost proportional to the quantity of required sensor.Additionally, modularity collection The standardization closing part allows the reduction of manufacturing cost.
The technology of the measurement FBG wavelength describing in this respect is fundamentally different from known prior art.To the greatest extent Pipe major part prior art is intended to find the wavelength of the peak reflectivity of grating, but this description content has used FBG to compose profile Knowledge determines the position with respect to inquiry source for the FBG centre wavelength of setted wavelength.
Referring now to Figure 1A, an equipment 1 is shown, including along single optical fiber 30 or multiple along branch out from main fiber Multiple FBG 50 (referring to Figure 1B, 2A and 2B) of optical fiber 30 distribution, multiple FBG 50 are included into one or many In individual sensor array 55.Each sensor array 55 is made up of N number of FBG array 50 of operation in same spectrum window, FBG Sensor along optical fiber 30 with away from source orientation or non-directional but known distance is separated, as shown in Figure 1A.Each sensing Device array 55 operates in different spectrum windows.Due to from all FBG 50 in array 55 all on same optical fiber 30, Array 55 can be defined as serial array, and this is different from parallel connected array hereinafter described.
Shown in another embodiment as shown in Figure 1B, each sensor array 55 includes being distributed in multiple optical fiber 30 FBG 50, is defined as parallel connected array.Each parallel connected array is arranged on by a single optical fiber by N number of (N=4 in Figure 1B) Sensor composition on each optical fiber that branch goes out, and be located at away from the distance of increment in source.This increment can rule can be irregular But it is known.Fig. 2 B applies for identical principle, in Fig. 2 B, has used multiple modules, as mentioned below.
Equipment 1 also includes：Including the interrogator 12 of one or more single modules 10, each module 10 is inquired at one One of sensor array 55 of the FBG of operation in spectrum window；If employing the module 10 (see Fig. 2) more than 1, The output of multiple modules is incorporated in an independent optical fiber 30 optical WDM device 60；Optional spectrum adds/deletes multichannel The output of multiple modules 10 can be segregated into each branch of optical fiber from main fiber 30 by multiplexer 65, often next passage, or Multiple passages (see Fig. 2) every time；One or more optional reference FBG on each sensor array 55 (does not show Go out), such a have known strained and temperature with reference to FBG.
The base unit of equipment 1 includes single module 10, in inquiry same spectrum window of positioning along in an independent optical fiber 30 One sensor array 55 with N number of FBG 50 of operation, as described in Figure 1A.As described below, to embodiment, can use Reference photodiode does the configuration substituting, and sees Fig. 6 A-6C.By with wavelength division multiplexer their output of multichannel sender, many Individual module 10 also can use, as shown in Figure 2 simultaneously.
Each module 10 is made up of the light source with narrow spectrum width (typically less than 1GHz), when light source is used for repeatedly launching lasting Between be τpPulse, make τpIt is shorter than in sensor array 55 light between continuous FBG 50 and propagate minimum time τ.Transmitting pulse Centre wavelength be forced in high numerical value λ+With low numerical value λ-Between alternately, λ+And λ-Difference more much smaller than the spectrum width of FBG 50 (such wavelength X+And λ-Pulse can be reflected by FBG), but be typically larger than spectrum width (such wavelength of each pulse λ+And λ-Pulse can be distinguished by spectrum).Therefore one mean wavelength λ of definableav=(λ++λ-)/2, λ+、λ-And λavAll should to the greatest extent may be used Can keep constant.
Alternate λ+And λ-Can be executed by different modes, in a kind of executive mode, as shown in Figure 3A, pulse with when Between interval T be issued, such T be more than in sensor array first light and the FBG of last between propagate total Time, and in λ+And λ-Between alternately.
(not shown) in another executive mode, to be spaced the λ of T transmitting+A large amount of trains of pulse follow in λ-A large amount of pulses After string.
The third possible executive mode, shown in Fig. 4 A, launches two pulses, a λ in time interval τ+Followed by one Individual λ-.For the third executive mode.τpIt is necessarily less than τ/2, two pulses can be different but it is also possible to be dissolved into respectively In the first half and the second half, there is mean wavelength λ+And λ-Independent pulse in (that is, initial wavelength begins to λ+, terminate close λ-).For reaching optimum efficiency, λ+And λ-Time between time between pulse or train of pulse is shorter than measured variable with meaningful Numerical value change the required time.
Light pulse is launched in an optical fiber 30, and according to an embodiment, light source 11 is a kind of by alternately high and low peak The fine coupling of electric light, the DFB laser diode (as the LD of Fig. 1) of temperature constant that the current impulse of electric current is ordered about.It is known that The center wavelength of light of such a DFB laser diode transmitting is related to driving current, therefore has the arteries and veins of different peak point currents Punching has different centre wavelengths.DFB laser diode module generally comprises one and is used for blocking reflected light return laser light diode Optical isolator and monitoring be launched light inside photodiode.
Behind optical coupling source, insert fiber coupler 15 or optical circulator.This allows reflected light to be redirected to photodetection On device 20 (PD in Fig. 1).Various other fiber arrays (in Fig. 1, C is used as general symbol(s)) can be inserted into fiber coupler 15 He Between sensor array 55, such as wavelength division multiplexer 60, adapter, optical fiber rotary joint 70 and interpolation/deletion multiplexer 65 (as shown in Figure 2).
If substituting circulator using fiber coupler 15, the second branch of fiber coupler 15 may comprise a reference FBG, as described below.
N number of FBG 50 of composition sensor array 55 is to have the grating Bragg falling into spectrum window internal reflection spectrum Optical fiber 50, spectral window is defined as the wave-length coverage that wavelength in the middle of FBG covers the scope of possible numerical value exceeding measured variable. Pulse λavMean wavelength more or less be located at spectrum window center.As in other TDM schemes, the maximum of FBG 50 is anti- Penetrate rate must sufficiently small (be led to by more than one sensor reflection) so that multipath reflection to be ignored.Generally, this Mean maximum reflectivity in the range of 1-2%.Therefore FBG 50 reflection light pulse, but each sensor is anti- Rate of penetrating depends on the numerical value in each sensing station for the measured variable, because measured variable affects the middle cardiac wave of FBG reflectance spectrum Long.Different wave length λ+And λ-Pulse also react varying strength, because their wavelength are in the diverse location of FBG reflectance spectrum.This from Can embody in Fig. 5 A and 5B, for two λ of different numerical valueBFBG spectrum, and λ+、λ-And λavPosition in FBG spectrum, With corresponding reflectance.
The pulse that each is launched, reflected signal be present in a series of have be equal to each FBG 50 light propagate In N number of pulse of interpulse delays time τ of time, N is the quantity of sensor in sensor array.Because delay time T is total It is to be longer than τp(pulse duration), therefore reflected impulse time upper difference.This shown in Fig. 3 A-3C, in one case, Pulse to each being launched as shown in Figure 3A, it will have the such reflection in 4 shown in Fig. 3 B (N=4), wavelength will be from Pulse is to pulse (λ+, λ-) alternately, peak strength (I simultaneously+, I-) alternately.Alternate λ is illustrated in the form of Fig. 4 A+And λ-Arteries and veins The pattern of punching, pulse also has different peak strengths, this be likely to be using have the DFB laser diode of different peak point currents with Change pulse wavelength.Fig. 3 B show is along the echo in the case of the array of 4 FBG of fiber distribution.
When launching two pulses in time τ, as described in Figure 4, echo is corresponding pulse pair, such as Fig. 4 B Shown.
The echo coming from N number of FBG 50 passes through fiber coupler 15 or circulator, and is redirected to photoelectricity On detector 20, wherein optical signal is converted to the signal of telecommunication.The response time of photoelectric detector 20 and electronic amplification circuit 25 should It is shorter than the pulse duration so that the electronic signal amplified is the loyal time reproduction of optical signal on substantially.
The process of the electronics of the signal of telecommunication and numeral is passed through in determination to the measured variable numerical value of each sensor on FBG array And realize, as mentioned below.
For this descriptive purpose, FBG 50 must have particular design and have the spectral response of well-characterized. Standard FBG generally has such a reflectance spectrum, in λBCentre wavelength have reflection peak, and have side in the every side of central peak Lobe.However, in order to realize this descriptive purpose, the height being shaped as not having minor lobe of the reflectance spectrum according to an embodiment This function.The technology that the FBG of so gaussian-shape can be well known for those skilled in the art manufactures.For such a function, The bandwidth △ λ of spectrumBThe wave-length coverage that reflectance is more than the 50% of maximum reflectivity can be defined as.
The effect of measured variable is to change central wavelength lambdaB.Measured variable can be temperature, strain or other change FBG The environmental condition of the reflectance spectrum of sensor.In the measurement range formulated by sensor, spectrum will transform to maximum △ λmax. Assume, for the light source 11 inquiring given sensor, there is wavelength XavCentered on narrow spectrum, then must set in a way The centre wavelength of meter FBG 50 and their reflectance spectrum width, at the two ends of measurement range, FBG reflectance is sufficiently large To lead to acceptable signal-to-interference ratio.Rule of thumb rule is it is necessary to design FBG 50 makes reflectance survey always greater than whole The 50% of the maximum of amount scope, in this case, will select λBIt is equal to measurement span center λav, and △ λmaxEqual to △ λB.However, the reflected signal of the existing equipment illustrating is generally much higher than with reflected signal produced by broadband light source, this is public Know, this is beneficial to be detected with high s/n ratio.
Once reflected signal changes into electronic signal, each sensor is executed with the electronics of the numerical value extracting measured variable Can be completed by various modes known in the art with digital process.Therefore, all of achievable this process are not enumerated here Possible mode.All these methods rely on the peak strength measuring each independent echo impulse or integral energy, and to this Plant the application of the algorithm of measured value.According to an embodiment, the sequence of N number of pulse is by an ADC chip (analog-to-digital conversion device) Digitized.Once by digitized, the integral energy of each echo impulse of inquiry can be by the persistent period τ related to each ripple Temporal window signal integration calculate.Then N numerical value obtains numerical value to the pulse that each is launched, and then passes through microprocessor Process, microprocessor can be a quick cpu chip or fpga chip, and it is programmed to perform some row steps Process, to extract the numerical value of the measured variable of each FBG 50 in array.
This Mathematical treatment is based on following methods.As described above, the pulse being launched into optical fiber 30 has two kinds of forms, higher Wavelength and the pulse of relatively low wavelength, respectively λ+And λ-.If having used a DFB laser diode, each type of pulse is entered Row difference peak drive current, also by difference, respective markers are I to the peak light intensity of each pulse+And I-.Assume in light source 11 Round relay loss α and FBG 50 between keeps constant or close to constant between two kinds of forms transmittings of pulse, simultaneously Also assume that measured variable is not changed with notable numerical value between pulse, then reflected impulse intensity is with respect to two kinds of form transmittings of pulse Pulse strength, differ only in due to the λ in the first pulse pattern and the second pulse pattern+And λ-Different centre wavelengths lead The difference of the reflectance causing.This is because FBG reflectance is the function of wavelength.If the FBG reflectance of the function as wavelength Given by function R (λ), then the poor D of the peak reflection intensity of the first pulse pattern and the second pulse pattern is：
D=α * [I+*R(λ+)-I-*R(λ-)] (1)
On the other hand, intensity with S is：
S=α * [I+*R(λ+)+I-*R(λ-)] (2)
The ratio A of two amounts, is defined as A=D/S, is：
A=[I+*R(λ+)-I-*R(λ-)]/[I+*R(λ+)+I-*R(λ-)] (3)
Define ratio C=I+/ I-, then equation (3) can also be write
A=[R (λ+)-C*R(λ-)]/[R(λ+)+C*R(λ-)] (4)
It can be seen that this ratio is unrelated with propagation loss α.For constant laser drive environment, ratio C is constant, and former It is a known quantity on then.Therefore amount A is the function of the determination of FBG reflectance spectrum R (λ) shape, numerical basis λ of AavAnd FBG Center sensor wavelength XBDifference.If shape R (λ) is so that the function being given by equation (4) being and measurement span (spectrum window) The monodrome of consistent span lengths, then numerical value A can uniquely draw FBG central wavelength lambdaBTwo kinds of mean wavelength λ with pulseav Difference.Due to λavKeep constant, therefore unique variable λBRelated to measured variable.
Known ratios C, also can calculate standard value B, be given by：
B=[R (λ+)-R(λ-)]/[R(λ+)+R(λ-)] (5)
As shown below, amount B can be directly related to the derivative of the spectral shape of FBG reflectance spectrum.
Numerical value A or B is used for associating the measurement of reflected impulse intensity with measured variable.Due to following can mention former Cause, numerical value B is preferred.
In order to explain how to realize in practice, row cite a plain example, and the shape of wherein grating spectrum is one Gaussian function, is expressed as：
R (λ)=Rmaxexp(-4In(2)(λ+-λ-)2/△λB 2) (6)
RmaxIt is peak reflectivity, λBIt is peak wavelength, △ λBIt is the half width at half maximum of Gauss spectrum.Due to λ+With λ-difference remote Less than spectral width △ λB, R (λ+) and R (λ -) difference close to function in wavelength XavDerivative be multiplied by λ+With λ-wavelength difference, It is expressed as δ λ.On the other hand, the denominator in equation (5) approaches in twice in mean wavelength λavReflectance, i.e. R (λ+)+R (λ-)=R (λav), with the function of equation 5, can draw：
B=-4In (2) Rmaxδλ(λzv-λB)2/△λB 2(7)
As can be seen that B is (λ in whole spectrumzv-λB) linear function.Other functions except the Gauss of R (λ) also may be used To use, but they cannot derive the linear function of B.Linear feedback simplifies standard, and B is to arbitrary λBThing for monodrome Avoid uncertain measurement in fact.Therefore, gaussian shape is effectively shape.If however, shape deviate from ideal Gaussian shape, The existing knowledge of the spectral shape of each grating then can be used to produce calibration curve.
Numerical value B can be calculated by the peak strength of pulse or integral energy.But the latter is it is preferred that being difficult because of it Produce noise.Further, B can averagely a large amount of pulses to reduce noise further.
In fact, ratio C can cause from pulse to pulse or produce change due to slow drift during drive electronics. For guaranteeing with the numerical value of correct C in the numerical value calculating B, measurement is favourable in real time.This can be by direct measurement by laser The pulse of diode emitter and realize, this be used for as FBG reflection signal normalization reference.Three kinds of sides realizing this measurement Formula is illustrated by Fig. 6 A-C.
In first embodiment, photodiode 120 can be inserted into the outfan of photoelectrical coupler 15 second branch (Fig. 6 A).Second is that embodiment (Fig. 6 B) is used in internal photodiode 120 in laser diode package.3rd embodiment (Fig. 6 C) employs the reflector of fiber coupler 15 second branch's end face or any device being inserted, then by light electric-examination Survey device 20 to detect, the same photoelectricity electroprobe of detection reflector detects the echo from sensor array 55.In latter event, must The fiber lengths between fiber coupler and reflecting surface must be adjusted so that reflected impulse with different from other all from sensing The time of device array echo out reaches photodiode.Detection and amplify after, these reference pulses by similarly amplify and Digitized is to provide peak value or the comprehensive numerical value similar to echo impulse.It is similar that other equivalent embodiments are proposed that Conclusion.
In wavelength X+N number of pulse train digitized after, can be by being carried out by the numerical value of time window to each pulse Integrating meter calculates to the i in each sequencethThe gross energy E of pulse+i.In wavelength X+Pulse train carry out to provide E-.Identical Process be applied to reference pulse, provide Eref+And Eref-.If in λ+Train of pulse follow in λ-Train of pulse after, then right In each independent pulse gross energy regard train of pulse quantity meansigma methodss.So, can be extracted for each from following formula by calculating ithThe B of pulseiN value：
Bi=((E+i/Eref+)-(E-i/Eref-))/((E+i/Eref+)+(E-i/Eref-)) (8)
As described in Fig. 3 C and 4C, wherein shadow region is equivalent to the gross energy of the first pulse in the sequence.As described above, BiNumerical value can directly with i in an arraythThe value of the measured variable of individual FBG is related.
Modules as described above 10 can be used for autonomous device, to measure a sensor array of N number of FBG 50 55.However, having different wave length λavLight source 11 multiple modules 10, can by access single optical fiber 30, for independent inquiry Ask multiple sensor arrays 55 of FBG 50.The spacing of the wavelength of different light sources have to be larger than spectrum window.This is divided by adopting The output of multiple modules 10 is multiplexed to a single optical fiber 30 ripple multiplexer reaches.Light source 11 includes laser diode, Laser diode is the type for so-called CWDM (CWDM), and it is the mark of optical telecommunications system foundation Accurate.The wavelength of this diode, between 1270 and 1610nm, is separated with 20nm, there is provided 18 kinds of different passages.In conjunction with up to 16 passages to independent optical fiber stock for multiplexer commercially can use.Multiplexing configuration (60,65) is in figure Illustrate in 2A.One 20nm interval is large enough to accommodate most of existing spectrum windows.The maximum capacity of therefore device 1 does not depend on Numerical value in spectrum window.Further, standardized wavelength means that FBG 50 also has a standardized design, this fall Low production cost.
The advantage that all light sources 11 are merged into independent optical fiber 30 is the writable light of all FBG 50 Fine 30.Therefore, along the FBG 50 of optical fiber 30 maximum quantity be the sensor inquired by each module 10 maximum number The product of the quantity of amount and sensor 10.
But further it is an advantage that all of sensor is by the single entrance addressing to optical fiber 30, from disparate modules 10 light retargetable is to branch.For example if it is desired to measure slewing, such as multiple position measurement temperature of engine rotor Degree or strain, then the fiber rotation connector 70 being arranged on armature spindle can be used between interrogator 12 and sensor, such as Described in Fig. 2A.After fiber rotation connector 70, different wavelength is sent to key light by adding/deleting multiplexer Fine corresponding branch.Such device can extract a passage (in a wavelength) and is transmitted into another optical fiber, or extracts One group of passage.For example, 8 in 16 passages, or 4 in 8 passages are sent to individual branches, as Fig. 2A institute State.Another embodiment according to Fig. 2 B, the fiber optic splitter being independent of wavelength can be used for the wavelength from disparate modules More or less in the multiple optical fiber forming multiple parallel sensor arrays, each optical fiber is inquired by disparate modules for distribution.This has The advantage that redundancy is provided, in case one of branch fault or fracture.If interrogator 12 is arranged on apart from FBG 50 When there is a big segment distance, same fibre comprises all request signals and is also advantageous.
Therefore, the modular structure of device 1 provides a lot of motilities.Various configurations for arranging FBG 50 are shown in In Fig. 7 A-7C.Module 10 independent operation, and associated sensor array 55 all can have different characteristics, is such as passing Different distance between sensor, or the different spectral widths of FBG 50.The latter determines measured variable scope, more determines Determine resolution.Therefore there is large span, the sensor of low resolution can be in conjunction with the high-resolution sensor of little span.Sensor Array 55 can be interlocked with regular spacing (Fig. 7 A), or is handed over the transducer beam of the different arrays of Small Distance binding at set intervals Fork, this can provide higher spatial resolution (Fig. 7 B).Or other sensor arrays 55 can be linked one by one (Fig. 7 C).The modular nature of device 1 also implies that cost increases with the module number using.Fig. 8 illustrates and adds/delete Except how multiplexer transmits signals to corresponding branch from one or more modules 10.
DFB laser diode is made into producing 1 nanosecond or less pulse.Between therefore for sensor in an array Minimum spacing can be as small as 10cm.The speed of electron process finally limits spacing.Because signal is lost in each reflection, sensor Limited quantity can be used in an array, typically 15.Because up to 16 passages can be with the multiplexing that can be purchased off the shelf Device combines, and the maximum capacity of device 1 may be up to 240 sensors.
Wavelength due to being launched by laser diode is the function of temperature, so needing the temperature control of a good diode System 13.This available thermoelectric refrigeration element is reached, using the signal of the temperature sensor being arranged on nearly diode as an error Signal, this is well known in the art to a certain extent.For long-time stability it is important that the central wavelength lambda of diodeav, And two kinds of pulse wavelength difference δ λ keeps constant within the time, or if they do not keep constant, monitoring is simultaneously Value for the scale of calibration instrument is important.It is known that laser diode degenerates with age, and therefore this two values have May drift about in time and slowly.In order to illustrate centre wavelength and numerical value δ λ in long drift it is necessary to one by very Good calibration stable reference sensor in known time.Reference sensor itself but to other sensors be related to similar Fiber Bragg Grating FBG, but its temperature and strain are precisely known.This can be such as hot by with another precision temperature sensor Quick resistance measurement FBG temperature and realize, or by keep FBG equilibrium temperature and strain other modes realize, this this Field is known.
The performance of TDM inquiry allows such a reference sensor to inquire with the other sensors on array simultaneously.For this reason, Sensor be necessarily placed at from inquiry unit have with a certain distance from, so from the echo with reference to grating using one of available Time window.This is reached by the distance adjusting from source to reference sensor.Reference sensor is arranged on optical fiber coupling Second branch of device 15, as long as in this position, on echo will fall wherein a time window.
It can be appreciated that each FBG has a known reflectance spectrum from the embodiment of foregoing description, also can claim It is with reference to reflectance spectrum, this can offset in response to the given ambient condition using FBG 50, therefore defines to each The skew of FBG 50.Each FBG 50 arranges different distance from light source 11 and receptor (in given array 55 Each there is interval), therefore allow to distinguish the reflection arteries and veins receiving from the FBG 50 of given array on the receptor time Punching.
When using more than an array 55, the FBG 55 on different arrays 55 is compared with another on another array 55 One FBG 50 has same distance from light source 11 and receptor.Therefore, need spectrum point between each of array 55 From, i.e. the FBG 50 of given array 55 responds all in given spectrum window.The spectrum window characterizing different arrays 55 should not weigh Folded.Therefore, when receiving reflected impulse, receptor can be reflected by the spectrum window of reflected impulse based on received moment and sign Pulse, clearly defines FBG.
Due to each array 55, in the window internal reflection of given spectrum, it is therefore necessary to there is interrogator, to be adapted to transmitting such Wavelength, this wavelength is corresponding to be given the wavelength reflection of spectrum window and avoids using broadband or tunable interrogator, as in background Technology segment refers to.Therefore, each array 55 there is a corresponding light source 11.The described light source 11 of corresponding array adapts to Transmitting in the spectrum window of respective array.Therefore, each array 55 and corresponding light source 11 operate in the spectrum window of each of which.
As described above, light source 11 does not need to launch in continuous wavelength scope to obtain " image " of reflected impulse, such as existing Have performed by technology.Because the shape with reference to reflectance spectrum is known to each FBG 50, and known variant Relatively small (less than the spectrum window of FBG 50), only has some discrete point needs in actual (skew) reflectance spectrum It is asked.In the above-described embodiments, shape is known as (or substantially) gaussian-shape, for gaussian shape, actual (skew ) only two points need to be determined to calculate actual reflectance spectrum with respect to reference to (known) reflected light in reflectance spectrum The change of spectrum.Accurate mensure to change, more complicated reflectance spectrums may need the wavelength of varying number.
For this reason, each light source 11 launches dispersion number not in whole spectrum window but on the corresponding spectrum window of light source 11 Wavelength (such as λ+And λ-).Due to λ+And λ-All in this spectrum window, therefore can be by defining the λ of transmitting+And λ-Between flat All wavelength XavThis situation of formalization.Therefore, each light source 11 is characterised by the phase in the consistent corresponding spectrum window of one of array 55 Answer mean wavelength, be transmitted to the discrete wavelength of fixed number (such as 2) around it.
Received within given time and wavelength in the pulse of each FBG 50 reflection, it is used for accurately defining The FBG 50 of reflected impulse.The actual reflectance spectrum that the pulse of reflection also reflects given FBG 50 is anti-from it Penetrate spectral shift how many (that is, the side-play amount of each FBG 50).Therefore also reflects the main bar to FBG 50 Part.The change of each sensor 50 can be calculated, as explained above.Can be by using school in the essential condition of given sensor 50 Quasi- moving of table and be resumed.
Although embodiment is described above and is also explained by accompanying drawing, for those skilled in the art without departing from this public affairs Substantially may make a change on the basis of opening.This change can be considered as the possible modification in open scope.

Claims (50)

1. a kind of sensor device is it is characterised in that include：
Interrogator, including light source, the transmitting of each light source has the pulse of certain wavelength, and described wavelength is around light source phase each described The mean wavelength answered；With
FBG array, one of corresponding described light source of each FBG array, and include many on an optical fiber The individual FBG for reflected impulse,
FBG in wherein given FBG array therebetween has a space interval, and this interval be enough in receptor Upper permission is produced the time difference between reflected impulse by each sensor on given FBG array；
Wherein each described FBG has corresponding spectral reflectance window, and spectral reflectance window includes a corresponding described light source Corresponding mean wavelength；
There is spectrum interval it is sufficient to allow on the receiver from each described FBG between the corresponding mean wavelength of wherein said light source SPECTRAL DIVERSITY between the pulse of sensor array reflection.
2. sensor device according to claim 1 is it is characterised in that each described light source is configured to around described light First respective wavelength of each the corresponding mean wavelength in source and the transmitting pulse of the second respective wavelength.
3. sensor device according to claim 1 is it is characterised in that described receptor includes processor, described place Reason device is applied to each described FBG array of each described light source corresponding, and the reference based on each FBG The prior art of reflectance spectrum, clearly determines each with the reflected wave pulses from the first corresponding pulses and the second corresponding pulses The peakdeviation of the actual reflectance spectrum of FBG.
4. sensor device according to claim 1 it is characterised in that described FBG array be arranged on many On individual optical fiber, each optical fiber has the FBG array of a given quantity.
5. sensor device according to claim 4 is it is characterised in that also include for being connected thereto multiple optical fiber Multiplexer, described interrogator be optically coupled to multiplexer for by described pulsing to multiple optical fiber.
6. a kind of sensor device is it is characterised in that include：
Interrogator, has the light source of the pulse of certain wavelength, described wavelength is around a mean wavelength including transmitting；With
Fiber Bragg Grating FBG (FBG) configures, and including FBG array, described sensor array is included on an optical fiber Multiple FBG, and be used for reflected impulse, thus on each FBG produce reflected impulse,
FBG on one of given FBG array betwixt has a space interval, and this space interval is connecing Receive on device enough to allow to be produced the time difference between reflected impulse by FBG each described；
Wherein FBG array has the spectral reflectance window including described mean wavelength.
7. sensor device according to claim 6 it is characterised in that described light source be used for being transmitted in mean wavelength attached Near first wave length and the pulse of second wave length.
8. sensor device according to claim 7 is it is characterised in that described receptor includes a processor, described The prior art of the reference reflectance spectrum based on described multiple FBG for the processor, adaptation is with corresponding from first The reflected impulse of wavelength and the second corresponding wavelength clearly determines the actual reflectance spectrum of each of multiple FBG.
9. a kind of device of the optical signalling interacting with Fiber Bragg Grating FBG (FBG) sensor configuration for measurement, institute State device to include：
FBG array, sensor array is arranged along single optical fiber, and each FBG is used for operating in given spectrum window, FBG is separated along single optical fiber with given distance, and each FBG on array has a known reflected light Spectrum, this reflectance spectrum can be displaced in the reflectance spectrum of reality under prescribed conditions, thus defining a side-play amount；With
Interrogator, described interrogator is connected on single optical fiber and comprises module, and described module is with being included in given spectrum window The interior discrete wavelength inquiry FBG array more than, interrogator receives the discrete wave more than of FBG The reflection of long optical signal, to determine the side-play amount of each FBG on array.
10. device according to claim 9 it is characterised in that described module be included in given spectrum window two from Scattered wavelength interrogation FBG array.
11. devices according to claim 10, it is characterised in that the described given distance that is spaced of FBG, lead to Time difference between the reflection of optical signalling that described interrogator receives.
, it is characterised in that also including a processor, described processor is operable for 12. devices according to claim 11 Be connected to interrogator, and be adapted to execute instruction for determining the instruction of specified criteria, under to described fixed condition it is known that Reflectance spectrum is displaced in the reflectance spectrum of each FBG reality on array.
A kind of 13. devices of the optical signalling interacting with Fiber Bragg Grating FBG (FBG) sensor configuration for measurement, its It is characterised by, described device includes：
Multiple FBG tactility apparatus arrays, sensor array is arranged along the multiple optical fiber branching out in main fiber, the plurality of array Each FBG having different spectrum windows and including operation in difference spectrum window, described FBG has one Known reflectance spectrum, this spectrum can experience skew in specified criteria, therefore defines side-play amount to each FBG；
Interrogator, is connected on main fiber and includes multiple modules, and each module uses an array of corresponding FBG not With the array of a FBG corresponding more than the pulse interrogation of in spectrum window, interrogator receives and is reflected by FBG And indicate the optical signalling of the side-play amount of each FBG.
14. devices according to claim 13 are it is characterised in that each module uses the array of corresponding FBG The pulse more than one of interior different spectrum windows, inquires the array of corresponding FBG, clearly to evaluate each FBG biography The side-play amount of the known reflectance spectrum of sensor.
15. devices according to claim 13 are it is characterised in that the FBG of described given array is along multiple optical fiber One of separated with given distance, on optical fiber, FBG is configured to：When optical signalling is reflected by FBG, energy Enough produce the time difference of described optical signalling pulse.
16. devices according to claim 13, it is characterised in that also including a multiplexer, are arranged on interrogator And multiple array between, multiplexer is used for for the output of multiple modules integrating with main fiber.
17. one kind are used for measuring the device of the optical signalling of Fiber Bragg Grating FBG (FBG) sensor configuration, described device bag Include：
Along the array of the FBG of single optical fiber setting, each described FBG has to be centered around and moves under change condition Peak reflectance wavelength known reflectance spectrum：With
Interrogator, described interrogator is connected to independent optical fiber and includes：
Module, is adapted to inquire the array of FBG using optical signalling, described optical signalling is with first wave length (λ+) or the Two wavelength (λ-) transmitting pulse；With
Receptor, to detect the pulse reflected by FBG array, i.e. reflected impulse, for determining at least one for adaptation The side-play amount of the peak reflectance wavelength of individual FBG.
18. devices according to claim 17 are it is characterised in that the additional FBG also including being arranged at additional optical fiber passes The array of sensor, the array of each additional FBG has different and unique peak reflectance wavelength；Described inquiry Device also includes additional module, is adapted to the array of the FBG additional with different optical signalling inquiries, described optical signalling Including with first wave length (λ+) or second wave length (λ-) pulse launched, wherein λ+And λ-For each additional module It is different and unique.
19. devices according to claim 17, it is characterised in that described receptor includes a photodiode, are used In optical signalling being changed into the electronic signal representing described optical signalling.
20. devices according to claim 19, it is characterised in that described receptor includes an amplifier, are used for putting Described greatly electronic signal.
21. devices according to claim 20 are it is characterised in that described receptor is for defeated with the described receptor of process The processing meanss operation communication of the electronic signal going out.
22. devices according to claim 21 it is characterised in that side-play amount based on peak reflectance wavelength, fit by processor Be made into by locate reason receptor output electronic signal determine act on measured at least one FBG.
23. devices according to claim 22 are it is characterised in that described processing equipment is adapted to for determining in effect At least one of temperature at least one sensor and strain.
It is characterised in that also including swivel joint, described swivel joint is set 24. devices according to claim 17 It is placed between interrogator and described single optical fiber, be used for making single optical fiber rotate with respect to described interrogator.
It is characterised in that described interrogator includes light source, described light source includes swashing 25. devices according to claim 17 Optical diode.
26. devices according to claim 25 it is characterised in that also including cooling element, for keeping described light source Temperature.
27. devices according to claim 26 are it is characterised in that described cooling unit includes the cooling unit of thermoelectricity.
28. devices according to claim 26 it is characterised in that also including temperature sensor, for measuring the temperature of light source Degree, and and then notify whether described cooling element is necessary to cool down described light source.
29. devices according to claim 25 are it is characterised in that also include the reference laser for monitoring described optical signal Diode.
30. devices according to claim 29 are it is characterised in that described reference laser diode is described in order to monitor The long-term wave length shift of light source.
31. devices according to claim 29 are it is characterised in that also include photo-coupler, for launch slave module Pulse steering configures to FBG and from described FBG sensing configuration, reflected impulse is directed to described receptor, described Photo-coupler there is the second branch, wherein said reference photodiode is arranged on the second branch of described photo-coupler On.
32. devices according to claim 17 it is characterised in that also including photo-coupler, for sending out from described module The pulse steering penetrated is to described FBG configuration, and described reflected impulse is directed to from the configuration of described FBG Described receptor.
A kind of 33. optical signallings being reflected by Fiber Bragg Grating FBG (FBG) sensing device including FBG for measurement Method, the method comprising the steps of：
Configure to described FBG from a light source and send：
At least one pulse in first wave length；With
In at least one pulse of second wave length,
Each pulse is at least separated with time interval T, and each pulse is shorter than unit interval T, passes from each FBG for difference The reflected impulse of sensor；
For at least one FBG, receive and measure following intensity：
Reflected impulse at least one pulse of first wave length；With
In the reflected impulse of at least one pulse of second wave length,
Calculate the peak reflectance wavelength of at least one described FBG.
34. methods according to claim 33 receive and measurement intensity it is characterised in that being executed by receptor.
35. methods according to claim 34 it is characterised in that described receptor be adapted to sufficiently fast response with So that distinguishing the reflected impulse from each sensor.
36. methods according to claim 34 are it is characterised in that described time interval T is from adjacent FBG The time interval that received on described receptor of reflected impulse.
37. methods according to claim 33 are it is characterised in that also include determining described peak reflectance wavelength with respect to institute State the side-play amount of the reference value of peak reflectance wavelength.
38. methods according to claim 37 are it is characterised in that also include being gone with the side-play amount of described peak reflectance wavelength Determine the value of the measured variable acting at least one FBG.
39. methods according to claim 33 are it is characterised in that also include with light source described in reference laser diode monitor Wavelength.
40. methods according to claim 39 are it is characterised in that also include using independent temperature sensor measurement reference The temperature of laser diode.
41. methods according to claim 40 are it is characterised in that also include controlling the temperature of described light source.
42. methods according to claim 41 are it is characterised in that control the temperature of light source to include：Cooling unit with thermoelectricity The described light source of part cooling.
43. methods according to claim 42 are it is characterised in that the temperature controlling light source is based on from temperature sensor Input, whether the temperature of described temperature sensor measurement light source deviates particular value.
44. methods according to claim 33 it is characterised in that be sent at least one of first wave length with the first intensity Pulse, is sent at least one pulse of second wave length with the second intensity, and the intensity of wherein measurement reflected impulse includes detection often The disappearance of individual pulse respective strengths.
45. methods according to claim 33 it is characterised in that to described FBG configure send pulse include to The FBG being arranged on multiple optical fiber sends.
A kind of 46. methods of Fiber Bragg Grating FBG (FBG) sensor configuration comprising FBG for inquiry, described side Method comprises the following steps：
FBG array to FBG configuration sends multiple optical signals, and each described optical signal is used for and single FBG array On the interaction of described FBG, each optical signal includes：
At least one pulse of corresponding first wave length；With
At least one pulse of corresponding second wave length,
Each corresponding mean wavelength of described optical signals is to characterize, corresponding first and second ripples in each optical signal described Length provides around described mean wavelength：
For at least one FBG of FBG array, receive and measure following intensity：
Reflected impulse at least one pulse of described first wave length；With
Reflected impulse at least one pulse of described second pulse；And
To FBG at least one described, calculate peak reflectance wavelength.
47. methods according to claim 46 are it is characterised in that to each optical signal, each pulse is at least spaced accordingly Time interval T, wherein each pulse is shorter than corresponding time interval T.
48. methods according to claim 46 receive and measurement intensity it is characterised in that being executed by receptor, described Receptor response sufficiently fast so that the reflected impulse from each FBG can be distinguished.
49. methods according to claim 46 are it is characterised in that each FBG array has following characteristics：In each FBG On array, all FBG of setting share corresponding spectrum window, and each FBG array is ask with a corresponding optical signalling Ask.
50. methods according to claim 49 are it is characterised in that corresponding mean wavelength in each described optical signalling Between, there is the spectrum accordingly composing window more than each FBG array and separate, enabling spectrum difference is carried out to each FBG array.
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